Today

Learning Objectives

Debris & Satellites in low Earth orbit

Image courtesy of European Space Agency

Active Earth Observing Satellites (EOS) (as of 8/31/2015)

  • Total number of operating satellites: 1,305
  • Total Earth Observing Satellites (EOS): 333
    • United States: 34%
    • China: 21%
    • Japan 6.3%

From the Union of Concerned Scientists Satellite Database and Pixalytics Blog

NASA’s Earth Observing System

Passive Remote Sensing

Moderate Resolution Imaging Spectroradiometer (MODIS)

Instrument

Terra launched in 1999, Aqua in 2002.

  • 2 Satellites (Terra & Aqua)
  • Viewing swath width of 2,330 km
  • Covers Earth every one to two days
  • Measures 36 spectral bands between 0.405 and 14.385 µm
  • 3 spatial resolutions – 250m, 500m, and 1,000m

MODIS Data Processing

  • Tracking and Data Relay Satellite System in White Sands, New Mexico
  • EOS Data and Operations System @ Goddard Space Flight Center in Greenbelt, MD
  • MODIS Adaptive Processing System (MODAPS)
  • 3 DAACs for distribution

MODIS products (a subset…)

Atmosphere

  • Aerosol
  • Total Precipitable Water
  • Clouds

Cryosphere Products

  • Snow Cover
  • Sea Ice and Ice Surface Temperature

Ocean Products

  • Sea Surface Temperature
  • Remote Sensing Reflectance
  • Sub-surface Chlorophyll-a Concentration
  • Particulate Carbon
  • Instantaneous Photosynthetically Available Radiation

Land Products

  • Surface Reflectance
  • Land Surface Temperature and Emissivity
  • Land Cover Products
  • Vegetation Index Products (NDVI and EVI)
  • Thermal Anomalies - Active Fires
  • Fraction of Photosynthetically Active Radiation (FPAR) / Leaf Area Index (LAI)
  • Evapotranspiration
  • Primary Productivity
  • Vegetation Continuous Fields
  • Water Mask
  • Burned Area Product

Example product workflow

Flow diagram showing the MODIS Land and Atmosphere Products required to generate the gridded, composited vegetation indices. From the MOD13 Algorithm Theoretical Basis Document.

Data formats

Most NASA EOS data distributed as HDF files, which are very similar to netCDF.

MODIS Gridding system

Collection-Level Naming Conventsions

MODIS/Terra Surface Reflectance 8-Day L3 Global 500m SIN Grid V005

  • MODIS/Terra - Instrument/Sensor
  • Surface Reflectance - Geophysical Parameter
  • 8-Day - Temporal Resolution
  • L3 - Processing Level
  • Global - Global or Swath
  • 500m - Spatial Resolution
  • SIN Grid - Gridded or Not
  • V005 - Collection Version

Filename Conventions

MOD09A1.A2006001.h08v05.005.2006012234657.hdf

  • MOD09A1 - Product Short Name
  • .A2006001 - Julian Date of Acquisition (A-YYYYDDD)
  • .h08v05 - Tile Identifier (horizontalXXverticalYY)
  • .005 - Collection Version
  • .2006012234567 - Julian Date of Production (YYYYDDDHHMMSS)
  • .hdf - Data Format (HDF-EOS)

MODIS Temporal Resolution

  • Daily
  • 8-Day
  • 16-Day
  • Monthly
  • Quarterly
  • Yearly

MODIS Spatial Resolution

  • Bands 1–2 250-meter
  • Bands 3–7 500-meter
  • Bands 8–36 1000-meter

Distributed Active Archive Centers (DAACs)

Accessing data

The Land Processes Distributed Active Archive Center has a nice “Data Discovery” Tool:

MODIS Products Table

Lists all available MODIS land products

Annual Land Cover Type

Description

Detailed layer information

Downloading: http/ftp access

or the LP DAAC2Disk Download Manager which builds a download script.

MODIS Web service

Subsets of MODIS Land Products through SOAP (Simple Object Access Protocol).

Libraries

library(raster)
#library(rgdal)
#library(ggplot2)
#library(ggmap)
#library(dplyr)
#library(tidyr)
#library(maps)
# New Packages
library(MODISTools)
datadir="data"

List MODIS products available through

GetProducts()
##  [1] "MCD12Q1"    "MCD12Q2"    "MCD43A1"   
##  [4] "MCD43A2"    "MCD43A4"    "MOD09A1"   
##  [7] "MOD11A2"    "MOD13Q1"    "MOD15A2"   
## [10] "MOD15A2GFS" "MOD16A2"    "MOD17A2_51"
## [13] "MOD17A3"    "MYD09A1"    "MYD11A2"   
## [16] "MYD13Q1"    "MYD15A2"